This invention relates to an agglutination analyzing vessel for analyzing agglutination patterns produced in response to immunological agglutination reaction and more particularly to a plate comprising a number of vessels for identifying various kinds of blood types with the aid of agglutination patterns of blood corpuscles or for detecting various kinds of antibodies and various antigens in sample solutions (like viruses, proteins and the like) with the aid of agglutination patterns of not only blood corpuscles but also of particles of material such as latex, carbon and the like.
In the conventional method of identifying blood types, for example, use is made of a winecup-shaped reaction vessel into which are quantitatively introduced a sample solution, 2 to 5% of test blood corpuscles suspended in saline solution, and a specified antiserum. Then, the mixture is set stationary to allow reaction between blood corpuscles and antiserum. Subsequently, it is centrifuged to sediment blood corpuscles. Then, the reaction vessel is rapidly wobbled so that the sedimented blood corpuscles are forcedly separated from one another. Then it is relatively slowly wobbled so as to collect the agglutinated particles at the center portion of the bottom surface of the vessel and form agglutinated patterns, to allow photometric detection of these patterns.
Such conventional blood type identifying method in which sedimentation is effected and then the reaction vessel is rapidly wobbled so as to separate the sedimented blood corpuscles from the bottom surface of the vessel can only be applied to the analysis of regular ABO blood type which shows strong agglutination, but could not be applied to many other immunological agglutination reactions which show weak agglutination, for example, a method of determining Rh blood subtype or detecting various kinds of incomplete antibodies. That is, if the agglutination reaction is weak, the blood corpuscles which have been clumped together become separated from each other when the reaction vessel is wobbled, and as a result, the particles are not collected at the lowest center portion of the reaction vessel.
In order to avoid the above mentioned drawback, the applicant has proposed in Japanese Patent Application No. 54-53,370 a method of identifying a blood type, by means of which the blood type showing weak agglutination due to incomplete antibodies as well as the blood type showing strong agglutination due to natural antibodies can be identified accurately. In this method, use is made of a cylindrical reaction vessel having a conical bottom and given amounts of blood corpuscles and antiserum are delivered into the vessel. After these substances are mixed, they are left to stand for a relatively short time, such as a half hour, and then the particle pattern formed on the bottom is detected to identify the blood type. In this method, when the blood corpuscles to be tested and the antibody react upon each other, the agglutinated blood cells are deposited over the whole bottom surface, like snow, but when the blood corpuscles do not react upon the antibody, the blood corpuscles are not agglutinated and settle down on the bottom separately and roll down the inclined bottom surface. Therefore, almost all corpuscles are collected at the lowest center portion of the bottom. In this manner, the pattern formed on the bottom by the settled blood corpuscles becomes different, depending upon the existence of agglutinating reaction between the blood corpuscles and antibody. Thus, by detecting the pattern on the bottom, it is possible to identify the blood type. The inventors have conducted various tests with using such a vessel and sometimes have encountered a problem that even in the agglutinating reaction, the agglutinated corpuscles slide down along the inclined bottom surface into the bottom center. In this case, it is difficult to determine the blood type accurately.
There has been also known a micro-plate having a number of cylindrical reaction vessels each having a concave or conical bottom from, for instance, German Patent Application Laid-open Publication No. 2,915,145. However, in the known micro-plate the above problem also occurs and particularly the weakly agglutinated corpuscles slide down the bottom surface into its center. Therefore, the agglutination patterns could not be formed precisely.